Postfix: Postfix local privilege escalation via hardlinked symlinks

As far as I can see, ISPConfig systems are not affected by this problem, because they use procmail as LDA and not postfix local delivery. Additionally, all current setups that are based on the perfect setup guide use Maildir for storing mails and Maildir is not affected (independant if procmail is used as lda or not).

Here is the security bulletin and explanation from the postfix developers: